Hybrid clustering and pairwise comparison document matching

ABSTRACT

An approach for determining similar text documents. The approach can calculate a first set of vectors for a first cluster of text documents and a first comparison vector for a text document of interest. The approach can select a subset of text documents from the cluster of text documents based on comparing the vectors from the first set of vectors to the first comparison vector and picking a predetermined number of closest comparison text documents. The approach can calculate a second set of vectors for the subset of documents and second comparison vector for the document of interest. The approach can generate similarity ratings for the subset of documents based on pairwise comparisons of the second comparison vector and the second set of vectors. The approach can generate a ranked list of the second cluster of text documents based on the similarity ratings.

TECHNICAL FIELD

The present invention relates generally to matching documents, and more specifically, to matching text documents based on a pairwise comparison of a subset of available documents.

BACKGROUND

Text similarity searches are a common and useful tool in many domains for identifying similar texts within a corpus of documents. The theory of text similarity in documents can be applied to any text document-based information. In particular, this functionality is especially useful in identifying duplicate document or similar defect reports during quality assurance testing.

A pairwise comparison of two texts is often useful when trying to determine similarity but attempting to execute a pairwise comparison over all possible pairs in a set of text documents is a resource intensive task, and not feasible in a real-world scenario. Limiting the pairwise comparison to a subset of the whole dataset would be computationally easier, but determining the appropriate subset is difficult and introduces risk. For instance, the risk of excluding what may be the desired best matching document from the subset. Merely filtering to a cluster from the overall set would yield a result that is too generic and encompasses too many documents.

BRIEF SUMMARY

According to an embodiment of the present invention, a computer-implemented method for determining similar text documents, the computer-implemented method comprising: calculating, by one or more processors, a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; selecting, by the one or more processors, a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; calculating, by the one or more processors, a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; generating, by the one or more processors, similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and generating, by the one or more processors, a ranked list of the second cluster of text documents based on the similarity ratings.

According to an embodiment of the present invention, a computer program product for determining similar text documents, the computer program product comprising: one or more non-transitory computer readable storage media and program instructions stored on the one or more non-transitory computer readable storage media, the program instructions comprising: program instructions to calculate a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; program instructions to select a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; program instructions to calculate a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; program instructions to generate similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and program instructions to generate a ranked list of the second cluster of text documents based on the similarity ratings.

According to an embodiment of the present invention, a computer system for determining similar text documents, the computer system comprising: one or more computer processors; one or more non-transitory computer readable storage media; and program instructions stored on the one or more non-transitory computer readable storage media, the program instructions comprising: program instructions to calculate a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; program instructions to select a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; program instructions to calculate a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; program instructions to generate similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and program instructions to generate a ranked list of the second cluster of text documents based on the similarity ratings.

Other aspects and embodiments of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cloud computing environment, according to embodiments of the present invention.

FIG. 2 depicts abstraction model layers, according to embodiments of the present invention.

FIG. 3 is a high-level architecture, according to embodiments of the present invention.

FIG. 4 is an exemplary detailed architecture, according to embodiments of the present invention.

FIG. 5 is a flowchart of a method, according to embodiments of the present invention.

FIG. 6 is a block diagram of internal and external components of a data processing system in which embodiments described herein may be implemented, according to embodiments of the present invention.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The following description discloses several embodiments of a text document comparison mechanism based on hybrid clustering and pairwise comparison. The herein described embodiments can calculate numeric vector representations for the set of existing documents. The specific document of interest can also be given a numeric vector representation at the time a query is provided from a user. Based on the vector representations, a nearest neighbor calculation is used to gather a neighborhood of the nearest documents (a subset of the set of existing documents). A pairwise comparison of document vectors in the subset neighborhood of documents against the specific document of interest (a separate and different process than the earlier nearest-neighbor approach) is performed in order to derive a final similarity ordering. The result is a list (ordered by similarity) of documents in the set that are most similar to the document of interest, e.g., sorted from the most similar to the least similar.

This mechanism is employed for increased computational efficiency, while also giving a precise ranking order of the most similar defects. Additional benefits of this mechanism include, but are not limited to, providing a precise ranking within this document subset, not exceeding a computational expense limit with the pairwise comparison when the underlying data set becomes large and a multi-phase process allowing for greater efficiency by first greatly reducing the eligible document set with the initial nearest-neighbor clustering, then providing precise ranking of most similar texts by performing more computationally expensive intensive pairwise computation on this smaller set.

It is to be understood that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed.

Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service's provider.

Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.

Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based e-mail). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds).

A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure that includes a network of interconnected nodes.

Referring now to FIG. 1, illustrative cloud computing environment 50 is depicted. As shown, cloud computing environment 50 includes one or more cloud computing nodes 10 with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone 54A, desktop computer 54B, laptop computer 54C, and/or automobile computer system 54N may communicate. Nodes 10 may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment 50 to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices 54A-N shown in FIG. 1 are intended to be illustrative only and that computing nodes 10 and cloud computing environment 50 can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser).

Referring now to FIG. 2, a set of functional abstraction layers provided by cloud computing environment 50 (FIG. 1) is shown. It should be understood in advance that the components, layers, and functions shown in FIG. 2 are intended to be illustrative only and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided:

Hardware and software layer 60 include hardware and software components. Examples of hardware components include mainframes 61; RISC (Reduced Instruction Set Computer) architecture-based servers 62; servers 63; blade servers 64; storage devices 65; and networks and networking components 66. In some embodiments, software components include network application server software 67 and database software 68.

Virtualization layer 70 provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers 71; virtual storage 72; virtual networks 73, including virtual private networks; virtual applications and operating systems 74; and virtual clients 75.

In one example, management layer 80 may provide the functions described below. Resource provisioning 81 provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing 82 provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may include application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal 83 provides access to the cloud computing environment for consumers and system administrators. Service level management 84 provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment 85 provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA.

Workloads layer 90 provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include mapping and navigation 91; software development and lifecycle management 92; virtual classroom education delivery 93; data analytics processing 94; transaction processing 95; and text document comparison 96.

It should be noted that the embodiments of the present invention may operate with a user's permission. Any data may be gathered, stored, analyzed, etc., with a user's consent. In various configurations, at least some of the embodiments of the present invention are implemented into an opt-in application, plug-in, etc., as would be understood by one having ordinary skill in the art upon reading the present disclosure.

FIG. 3 is a high-level architecture for performing various operations of FIG. 5, in accordance with various embodiments. The architecture 300 may be implemented in accordance with the present invention in any of the environments depicted in FIGS. 1-4, among others, in various embodiments. Of course, more or less elements than those specifically described in FIG. 3 may be included in architecture 300, as would be understood by one of ordinary skill in the art upon reading the present descriptions.

Each of the steps of the method 500 (described in further detail below) may be performed by any suitable component of the architecture 300. A processor, e.g., processing circuit(s), chip(s), and/or module(s) implemented in hardware and/or software, and preferably having at least one hardware component may be utilized in any device to perform one or more steps of the method 500 in the architecture 300. Illustrative processors include, but are not limited to, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., combinations thereof, or any other suitable computing device known in the art.

Architecture 300 includes a block diagram, showing a corpus temporal analysis system determining an obsolete corpus, to which the invention principles may be applied. The architecture 300 comprises a client computer 302, a text document matching component 308 operational on a server computer 304, a text document repository 310 and a network 306 supporting communication between the client computer 302 and the server computer 304.

Client computer 302 can be any computing device on which software is installed for which an update is desired or required. Client computer 302 can be a standalone computing device, management server, a web server, a mobile computing device, or any other electronic device or computing system capable of receiving, sending, and processing data. In other embodiments, client computer 302 can represent a server computing system utilizing multiple computers as a server system. In another embodiment, client computer 302 can be a laptop computer, a tablet computer, a netbook computer, a personal computer, a desktop computer or any programmable electronic device capable of communicating with other computing devices (not shown) within user persona generation environment via network 306.

In another embodiment, client computer 302 represents a computing system utilizing clustered computers and components (e.g., database server computers, application server computers, etc.) that act as a single pool of seamless resources when accessed within install-time validation environment of architecture 300. Client computer 302 can include internal and external hardware components, as depicted and described in further detail with respect to FIG. 5.

Server computer 304 can be a standalone computing device, management server, a web server, a mobile computing device, or any other electronic device or computing system capable of receiving, sending, and processing data. In other embodiments, server computer 304 can represent a server computing system utilizing multiple computers as a server system. In another embodiment, server computer 304 can be a laptop computer, a tablet computer, a netbook computer, a personal computer, a desktop computer, or any programmable electronic device capable of communicating with other computing devices (not shown) within install-time validation environment of architecture 300 via network 306.

Network 306 can be, for example, a local area network (LAN), a wide area network (WAN) such as the Internet, or a combination of the two, and can include wired, wireless, or fiber optic connections. In general, network 306 can be any combination of connections and protocols that will support communications between client computer 302 and server computer 304.

Text document matching component 308, operational on server computer 304, can look for the closest matching document in a large pool of documents. Text document matching component 308 can calculate numeric vector representations for the provided document pool. It should be noted that text document matching component 308 can also calculate a numeric vector representation of the document of interest at the time a query is provided from a user.

Based on the vector representations, text document matching component 308 can perform a nearest neighbor calculation to gather a neighborhood (a portion of the large pool of documents) of the nearest documents to the document of interest. Text document matching component 308 can perform a pairwise comparison of document vectors in the subset neighborhood of documents to the document of interest (a different process than performed to determine the nearest neighbors) to generate a similarity ordering. The result is an ordered list of documents in the set that are most similar to the document of interest.

Text document repository 310 is a pool of documents available for use by a user. Text document repository can contain any number of documents that can be related or unrelated in content, date, authorship, etc. Text document repository 310 can also contain references to other collections of documents that are available for use by a user.

FIG. 4 is an exemplary detailed architecture for performing various operations of FIG. 5, in accordance with various embodiments. The architecture 400 may be implemented in accordance with the present invention in any of the environments depicted in FIGS. 1-3 and 5, among others, in various embodiments. Of course, more or less elements than those specifically described in FIG. 4 may be included in architecture 400, as would be understood by one of skill in the art upon reading the present descriptions.

Each of the steps of the method 500 (described in further detail below) may be performed by any suitable component of the architecture 400. A processor, e.g., processing circuit(s), chip(s), and/or module(s) implemented in hardware and/or software, and preferably having at least one hardware component, may be utilized in any device to perform one or more steps of the method 500 in the architecture 400. Illustrative processors include, but are not limited to, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., combinations thereof, or any other suitable computing device known in the art.

Architecture 400 provides a detailed view of at least some of the modules of architecture 300. Architecture 400 can comprise a text document matching component 308, which can further comprise a vector assignment component 402, a cluster generation component 404, a pairwise comparison component 406, and a rating component 408.

In one embodiment of the present invention, vector assignment component 402 can tokenize the body of a text document. In another aspect of the embodiment, vector assignment component 402 can calculate two numeric vector representations, created from unigram and bigram occurrences of tokens in the tokenized body of the text document. For example, the tokenization can be based on word and phrase occurrence frequencies in the processed document text. The resultant vectors now exist in a high-dimensional space. It should be noted that the first (unigram) vector is calculated from a shorter summary of the document text, while the second (bigram) vector is calculated from the full text document. It should further be noted that the specific document of interest is also processed to yield these two numeric vector representations, e.g., at the time a query, associated with the document of interest, is provided.

In another embodiment of the present invention, cluster generation component 404 can provide the capability to generate a cluster, i.e., a neighborhood of similar documents. The cluster of documents is a subset of the initial pool of documents available from text document repository 310, or from other sources. Cluster generation component 404 can create a cluster based on a comparison of the numeric vectors in the high-dimensional space. Cluster generation component 404 can compare the first (unigram) vector to the first (unigram) vector generated for the document of interest and select a predetermined number of vectors that are closest in value to the vectors calculated for the document of interest. It should be noted that the resultant cluster of documents are documents comprising a subset of documents more relevant to the document of interest than the total documents available in text document repository 310.

In another embodiment of the present invention, pairwise comparison component 406 can provide the capability, within this smaller neighborhood of documents, a pairwise comparison of the second (bigram) vector of the documents in the neighborhood against the specific document of interest's second (bigram) vector (a different comparison than the earlier nearest-neighbor approach) to generate similarity ratings for the document of interest and the neighborhood of documents. It should be noted that pairwise comparison component 406 can include other metrics, e.g., techniques including Manhattan distance and Euclidean distance, in the pairwise comparison to generate the similarity ratings.

Ranking component 408 can analyze the similarity ratings to generate a precise ordering of the documents in the neighborhood. The result of the analysis is a document list, ordered by similarity from most similar to least similar, of the documents in the neighborhood as compared to the document of interest. It should be noted that a similarity rating can be, for example, a numerical score ranging from 0 to 1 or from 1 to 100, etc., wherein a higher score indicates a closer similarity between the documents.

FIG. 5 is an exemplary flowchart of a method 500 for determining similar text documents. At step 502, an embodiment can calculate, via vector assignment component 402, numeric vectors for a cluster of text documents. At step 504, the embodiment can create, via cluster generation component 404, a cluster of text documents based on their numeric vectors. At step 506, the embodiment can generate, via pairwise comparison component 406, similarity ratings for text documents associated with the cluster. At step 508, the embodiment can rank, via ranking component 408, similar documents based on the similarity ratings. At step 510, the embodiment can select, via text document matching component 308, the most similar text document based on the ranking.

FIG. 6 depicts computer system 600, an example computer system representative of client computer 302 and server computer 304. Computer system 600 includes communications fabric 602, which provides communications between computer processor(s) 604, memory 606, persistent storage 608, communications unit 610, and input/output (I/O) interface(s) 612. Communications fabric 602 can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric 602 can be implemented with one or more buses.

Computer system 600 includes processors 604, cache 616, memory 606, persistent storage 608, communications unit 610, input/output (I/O) interface(s) 612 and communications fabric 602. Communications fabric 602 provides communications between cache 616, memory 606, persistent storage 608, communications unit 610, and input/output (I/O) interface(s) 612. Communications fabric 602 can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric 602 can be implemented with one or more buses or a crossbar switch.

Memory 606 and persistent storage 608 are computer readable storage media. In this embodiment, memory 606 includes random access memory (RAM). In general, memory 606 can include any suitable volatile or non-volatile computer readable storage media. Cache 616 is a fast memory that enhances the performance of processors 604 by holding recently accessed data, and data near recently accessed data, from memory 606.

Program instructions and data used to practice embodiments of the present invention may be stored in persistent storage 608 and in memory 606 for execution by one or more of the respective processors 604 via cache 616. In an embodiment, persistent storage 608 includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage 608 can include a solid state hard drive, a semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information.

The media used by persistent storage 608 may also be removable. For example, a removable hard drive may be used for persistent storage 608. Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage 608.

Communications unit 610, in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit 610 includes one or more network interface cards. Communications unit 610 may provide communications through the use of either or both physical and wireless communications links. Program instructions and data used to practice embodiments of the present invention may be downloaded to persistent storage 608 through communications unit 610.

I/O interface(s) 612 allows for input and output of data with other devices that may be connected to each computer system. For example, I/O interface 612 may provide a connection to external devices 618 such as a keyboard, keypad, a touch screen, and/or some other suitable input device. External devices 618 can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data used to practice embodiments of the present invention can be stored on such portable computer readable storage media and can be loaded onto persistent storage 608 via I/O interface(s) 612. I/O interface(s) 612 also connect to display 620.

Display 620 provides a mechanism to display data to a user and may be, for example, a computer monitor.

The components described herein are identified based upon the application for which they are implemented in a specific embodiment of the invention. However, it should be appreciated that any particular component nomenclature herein is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature.

The present invention may be a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.

Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.

These computer readable program instructions may be provided to a processor of a computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be accomplished as one step, executed concurrently, substantially concurrently, in a partially or wholly temporally overlapping manner, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

Moreover, a system according to various embodiments may include a processor and logic integrated with and/or executable by the processor, the logic being configured to perform one or more of the process steps recited herein. By integrated with, what is meant is that the processor has logic embedded therewith as hardware logic, such as an application specific integrated circuit (ASIC), a FPGA, etc. By executable by the processor, what is meant is that the logic is hardware logic; software logic such as firmware, part of an operating system, part of an application program; etc., or some combination of hardware and software logic that is accessible by the processor and configured to cause the processor to perform some functionality upon execution by the processor. Software logic may be stored on local and/or remote memory of any memory type, as known in the art. Any processor known in the art may be used, such as a software processor module and/or a hardware processor such as an ASIC, a FPGA, a central processing unit (CPU), an integrated circuit (IC), a graphics processing unit (GPU), etc.

It will be clear that the various features of the foregoing systems and/or methodologies may be combined in any way, creating a plurality of combinations from the descriptions presented above.

It will be further appreciated that embodiments of the present invention may be provided in the form of a service deployed on behalf of a customer to offer service on demand.

The descriptions of the various embodiments of the present invention have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. 

What is claimed is:
 1. A computer-implemented method for determining similar text documents, the computer-implemented method comprising: calculating, by one or more processors, a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; selecting, by the one or more processors, a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; calculating, by the one or more processors, a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; generating, by the one or more processors, similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and generating, by the one or more processors, a ranked list of the second cluster of text documents based on the similarity ratings.
 2. The computer-implemented method of claim 1, wherein the first vector of interest and the vectors in the first cluster of vectors are unigram numeric vectors based on unigram occurrences of tokens in the first cluster of text documents and the document of interest.
 3. The computer-implemented method of claim 2, wherein the second vector of interest and the vectors in the second cluster of vectors are bigram numeric vectors based on bigram occurrences of tokens in the second cluster of text documents and the document of interest.
 4. The computer-implemented method of claim 2, wherein the unigram numeric vectors are generated based on shorter summaries of the first cluster of text documents and the document of interest.
 5. The computer-implemented method of claim 1, wherein the ranked list is sorted from most similar to least similar.
 6. The computer-implemented method of claim 1, further comprising: storing, by the one or more processors, the first cluster of vectors in a vector repository; and storing, by the one or more processors, the second cluster of vectors in a vector repository.
 7. The computer-implemented method of claim 1, further comprising: selecting, by the one or more processors, a most similar document based on the ranking.
 8. A computer program product for determining similar text documents, the computer program product comprising: one or more non-transitory computer readable storage media and program instructions stored on the one or more non-transitory computer readable storage media, the program instructions comprising: program instructions to calculate a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; program instructions to select a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; program instructions to calculate a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; program instructions to generate similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and program instructions to generate a ranked list of the second cluster of text documents based on the similarity ratings.
 9. The computer program product of claim 8, wherein the first vector of interest and the vectors in the first cluster of vectors are unigram numeric vectors based on unigram occurrences of tokens in the first cluster of text documents and the document of interest.
 10. The computer program product of claim 9, wherein the second vector of interest and the vectors in the second cluster of vectors are bigram numeric vectors based on bigram occurrences of tokens in the second cluster of text documents and the document of interest.
 11. The computer program product of claim 9, wherein the unigram numeric vectors are generated based on shorter summaries of the first cluster of text documents and the document of interest.
 12. The computer program product of claim 8, wherein the ranked list is sorted from most similar to least similar.
 13. The computer program product of claim 8, further comprising: program instructions to store the first cluster of vectors in a vector repository; and program instructions to store the second cluster of vectors in a vector repository.
 14. The computer program product of claim 8, further comprising: program instructions to select a most similar document based on the ranking.
 15. A computer system for determining similar text documents, the computer system comprising: one or more computer processors; one or more non-transitory computer readable storage media; and program instructions stored on the one or more non-transitory computer readable storage media, the program instructions comprising: program instructions to calculate a first cluster of vectors for a first cluster of text documents, respectively and a first vector of interest for a document of interest; program instructions to select a predetermined number of text documents from the first cluster of text documents to include in a second cluster of text documents based on a comparison of the first vector of interest with vectors in the first cluster of vectors being closest in value to the first vector of interest; program instructions to calculate a second cluster of vectors for the second cluster of text documents, respectively and a second vector of interest for the document of interest; program instructions to generate similarity ratings for the second cluster of text documents based on pairwise comparisons of the second vector of interest and the vectors of the second cluster of vectors; and program instructions to generate a ranked list of the second cluster of text documents based on the similarity ratings.
 16. The computer system of claim 15, wherein the first vector of interest and the vectors in the first cluster of vectors are unigram numeric vectors based on unigram occurrences of tokens in the first cluster of text documents and the document of interest.
 17. The computer system of claim 16, wherein the second vector of interest and the vectors in the second cluster of vectors are bigram numeric vectors based on bigram occurrences of tokens in the second cluster of text documents and the document of interest.
 18. The computer system of claim 16, wherein the unigram numeric vectors are generated based on shorter summaries of the first cluster of text documents and the document of interest.
 19. The computer system of claim 15, wherein the ranked list is sorted from most similar to least similar.
 20. The computer system of claim 15, further comprising: program instructions to store the first cluster of vectors in a vector repository; program instructions to store the second cluster of vectors in the vector repository; and program instructions to select a most similar document based on the ranking. 